Electrical ribbon cable connector



Nov. 8, 1966 H. J. VANSTROM v 3,284,756

ELECTRICAL RIBBON CABLE CONNECTOR Filed May 19, 1965 INVENTOR HAROLD J. VANSTROM MLLQNLMP AT TORNE Y United States Patent Ofifice 3,284,756 Patented Nov. 8 1966 7 3,284,756 ELECTRICAL RIBBON CABLE CONNECTOR Harold J. Vanstrom, 210 Easy St., Mountain View, Calif. Filed May 19, 1965, Ser. No. 456,909 Claims. (Cl. 339-174) The present invention relates generally to electrical cable connectors and, more specifically, to means for interconnecting a pair of alike flat, multiconductor electrical ribbon cables.

The particular type of ribbon cable to be interconnected by the connector of this invention is generally in the form of a ribbon or tape of an insulating material, such as a flexible plastic, having thin, fiat, metallic strips imbedded therein which are disposed in parallel spaced relationship to each other. Ribbon cables of this type may have an overall width up to several inches with a thickness of a small fraction of an inch and include anywhere from 2 to 50 or more conductors. The flat conductors are generally made of copper, aluminum or the like which are providedwith a coating or a surface treatment which enables adherence of the plastic insulating material thereto.

Many problems exist when attempting to interconnect a pair of these flexible, multiconduct-or ribbon cables. The flexibility of the material together with the relatively small sizes of the individual conductors, the spaced relationship of the conductors, the necessity for establishing uniform and desired contact pressures between individual conductors for a releasable connection and for preventing inadvertent separation of the interconnected cables, all cooperate to define a portion of these problems. Not only have prior connectors been impractical and expensive in both manufacture and assembly, but the reliability of the connectors has left much to be desired in view of the delicate nature of the conductors. Additionally, when the conductors are made of aluminum, soldering techniques cannotbe used for making connections.

The described flat, multiconductor, electrical ribbon cable is supplied by manufacturers in continuous lengths and it is convenient, as Well as economical, to cut the desired length of such cables from the stock material.

Thereafter it is desirable to interconnect such cables by means of a single connector without extensive treatment, handling or modification of the cable and particularly without the necessity of individually soldering of theconductors which is time consuming, creates a permanent connection and is not available for aluminum conductors. It is also important that such connectors be of minimum weight and occupy a minimum of space, and that cables may easily be disconnected for repair or replacement.

It is, therefore, one important object of the present invention to provide an improved means for interconnecting flat, multiconductor ribbon cables.

It is another object of this invention to provide an interconnecting means which receives the ribbon cables to be interconnected and which interconnect the conductors releasably, yet positively, and secures the same against inadvertent separation.

It is a further important object of the invention to provide a means for interconnecting multiconductor, flat ribbon cables to one another without utilizing soldering techniques.

It is another object of this invention to provide a connection means for multiconductor flat ribbon cables which interconnects the conductor exposed end portions of a pair of ribbon cables and which releases both cables simultaneously. In other words, the connector of this invention does not require a permanent connection with either one of the ribbon cables to be interconnected.

It is still another important object of the invention to provide a means for interconnecting flat, multiconductor electrical ribbon cables wherein adequate contact pressure between the interconnected conductors is maintained and in which the contact pressure between any one pair of conductors is substantially independent of the contact pressure between any other pair of conductors.

It is still another object of this invention to provide a connector for interconnecting flat, multiconductor electrical ribbon cables which makes possible the rapid connecting and releasing without damage to the connector or the individual conductors and in which each pair of interconnected conductors is subjected to a resilient pressure to assure acontact having negligible electrical contact resistance. v

Briefly, the electrical ribbon cable connector of this invention utilizes a hollow plastic cylindrical body having a longitudinal slot-like opening extending along its length and defining a pair of opposite edges. The edges are provided with grooves to receive and space the individual conductors of the ribbon calbes to be interconnected. After the stripped conductors are placed to extendinto the hollow cylindrical body in lengthwise overlapping relation, a resilient and expandable core is stretched and inserted through the opening into the hollow interior where, upon expansion, it urges the overlapping conductors against one another for good electrical contact.

Further objects and advantages of the present invention will become apparent to those skilled in the art to which the invention pertains as the ensuing description proceeds.

The features of novelty that are considered characteristic of this invention are set forth with particularity in the appended claims. The organization and method of operation of the invention itself will best be understood from the following description when read in connection with the accompanying drawing in which:

FIGURE 1 is an isometric view showing a preferred form of the connector of this invention together with a portion of the electrical ribbon cables;

FIGURE 2 is an enlarged, transverse sectional view through the connector arrangement of FIGURE 1, as taken substantially as indicated by lines 22 of FIGURE 1; and

FIGURE 3 is an isometric view showing the stretching of the expandable core member prior to insertion into the connector body.

Referring now to the drawings and particularly to FIGURES 1 and 2 thereof, there is shown the connector of this invention generally indicated at 10. Connector 10 comprises a hollow cylindrical body 12 having a longitudinal slot or opening 14 extending along its full length and providing access to the hollow interior. The interior of body 12 may be formed by a cylindrical bore 16. Accordingly, the cross section of body 12 generally conforms to an annulus having an arc length greater than Slot 14 defines a pair of opposed slot edges 18 and 20 each of which is provided with conductor reception means such as plurality of notches 22 and 23 respectively for a purpose to be explained hereinafter. Bore 16 accommodates a stretchable core 24, made of a resilient material such as neoprene, silicon rubber, or the like, which may include gripping means at either end thereof as shown at 26.

Also shown in the drawings is a pair of flat, flexible ribbon cables 30 and 32 which are interconnected by connector 10. Ribbon cable 30 comprises a ribbon or tape of insulatingmaterial 34 which may be a flexible plastic and which has imbedded therein a plurality of thin, fiat metallic conductors such as the four conductors 36, 37, 38 and 39 shown. Ribbon cable 32 is substantially identical to ribbon cable 30 and includes a plastic ribbon or tape 40 having imbedded therein a plurality of conductors such as the four conductors 41, 42, 43 and 44 shown.

It is to be understood, however, that ribbon cables generally include more than four conductors, and that the four conductors shown in the drawing are merely illustrative of ribbon cables.

The end portions of ribbon cables 30 and 32 to ,be interconnected have their insulating covering removed, as shown at 46 and 48, to expose the conductive strips to be connected.

Referring now particularly to FIGURE 2, there is illustrated the interconnection of individual conductors. Conductor 39 of ribbon cable 30 and conductor 44 of the ribbon cable 32 are each inserted into the interior of body 12 from opposite sides and are received, respectively, by reception means 22 and 23. The length of conductors 39 and 44 inserted into the interior or body 12 is selected to be sufficiently long to form a lengthwise overlapping portion which is at least as long as the width of a conductor, Core 24, being of resilient material, urges the lengthwise overlapping portions of conductors 39 and 44 into intimate contact with one another against the peripheral surface of bore 16 to thereby provide a positive electrical Contact between the conductor to be interconnected.

Reception means for the individual conductors, such as recesses 22 and 23 in edges 18 and 20, provide a positive lateral guide for placing of the individual conductors so that conductors to be interconnected are properly aligned with one another. Accordingly, each of recesses 22 and 23 lie in a common diametrical plane of body 12. Also, since the plural conductive strips in the ribbon cables are generally of equal width and lateral separation, the recesses likewise are of equal width and lateral separation. Generally speaking, the recesses in edges 18 and 20 conform to the conductor strips of the ribbon cables to be interconnected. It is also to be noted that the connector of this invention may have more recesses than are actually required for a particular ribbon cable so that it may be used for different ribbon cables. For example, a connector constructed in accordance with this invention for a 20 conductor ribbon cable may be used for any ribbon cable having a lesser number of conductive strips, or even for several cables, such as two ribbon cables of say eight conductive strips each.

A suitable connector for practicing the instant invention may have a cylindrical body 12 constructed of a plastic insulating material such as Lucite or the like, having an outer diameter of approximately 4 inch and an interior bore of approximately inch. Slot 14 may be formed by cutting a 90 wedge lengthwise out of cylindrical body 12 so that the arc length of the remaining cylindrical annulus is approximately 270. The wedge cut out of body 12 to form slot 14 may, of course, vary, the important criteria being that the slot width is less than the maximum interior width so that a constriction is formed for holding core 24 firmly in place. The greater the constriction, the more securely will core 24 be held. On the other hand, the constriction should be sufficiently wide to permit insertion of stretchable core 24 into the bore 16.

Resilient core 24 may be constructed out of a resilient material, such as is commonly employed in making O-ring seals, as for example, neoprene, silicon rubber or the like. Dimensionally, it may have a diameter along its operating section which, in the unstretched state, is approximately /a inch, i.e., somewhat larger than bore 16. Gripping means 26 may be of any suitable shape to positively engage a stretching tool such as a pair of stretching pliers 50 shown in FIGURE 3.

Referring now to FIGURE 3, there is shown, by Way of example a suitable stretching tool 50 having jaws 51 and 52 for positively engaging the end portion of core 24, and including an actuating mechanism for forcing the jaws apart to stretch core 24 to decrease its diameter along the operative section for insertion in the interior of body 12, When sufliciently stretched, so that its diameter is less than the width of the constriction, core 24 may be lifted out of or into bore 16 through slot 14 to release or to interconnect the conductive strips.

In operation of this invention, the end portions of the ribbon cables to be connected are stripped of the insulating covering to expose short end portions having bare conductors. Thereafter, core 24 is removed by stretching and the bare cables are inserted, across opposite edges, into bore 16 where they form lengthwise overlapping portions. Recesses 22 and 23, respectively, provide lateral guide means for the individual bare conductors and assist to maintain them separate and out of contact with one another. After insertion of the individual conductors into bore 16, core 24 is stretched once more and placed, through slot 14, into the bore. After release of the stretching force, core 24 expands to urge the lengthwise overlapping bare conductor into good electrical contact with one another against the peripheral surface of bore 16.

When there is no need to connect the ribbon cables releasably the end portions of core 24 may be cut off to be flush with the end faces of connector body 12. Also core 24 may be formed from a continuous roll of resilient material which is cut to the length to suit. In this case the individual cores do not have the gripping means on opposite end portions so that the stretching tool requires jaws to hold the end portions firmly. A suitable jaw for such application is self closing which increases its grip as the engaged core is stretched.

There has been described a ribbon cable connector for interconnecting a pair of ribbon cables by means of placing the individual conductor into lengthwise overlapping relation within the interior surface of a circular bore. A resilient expandable core is inserted into the bore to urge the lengthwise overlapping conductors into good electrical contact with one another by pressing them against the interior bore surface.

While the above detailed description has shown, described and pointed out the fundamental novel features of the invention as applied to various embodiments, it Will be understood that various omissions and substitutions and changes in the form and details of the device illustrated may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. A connector assembly for interconnecting a pair of flat, flexible ribbon cables having a plurality of laterally separated electrical conductors disposed within an insulating covering and having said insulating covering removed from the end portions to be interconnected to expose said conductors, said connector assembly com-.

prising:

a substantially rigid, hollow insulator body having a longitudinal opening defining a pair of spaced edges, the exposed conductor end portions of the pair of ribbon cables to be interconnected being respectively received, from opposite sides and over said spaced edges through said longitudinal opening by the interior of said hollow body for lengthwise overlapping contact of the individual conductors to be connected; and

resilient core means insertable into said hollow body through said longitudinal opening, said core means having a cross section 'along its length which is greater than the cross section of the interior of said hollow body to securely urge overlapping conductor end portions against one another and the interior surface of said hollow body.

2. A connector assembly for interconnecting a pair of fiat, flexible ribbon cables having a plurality of laterally separated electrical conductors disposed Within an insulating covering [and having said insulating covering removed from the end portions to be interconnected to expose said conductors, said connector assembly comprising:

a substantially rigid, hollow insulator body having a longitudinal opening defining a pair of spaced edges;

a plurality of laterally spaced reception means in each or" said spaced edges, the exposed conductor end portions of the pair of ribbon cables to be interconnected being respectively received, from opposite sides, by said reception means and extending through said longitudinal opening into the interior of said hollow body for a distance sufficient to cause a lengthwise overlap of the individual conductors to be connected; and

resilient core means insertable into the interior ofs-aid hollow body through said longitudinal opening, said core means having a cross section along its length which is greater than the cross section of the interior of said hollow body to securely urge overlapping conduct-or end portions against one another and the interior surface of said hollow body.

3. A connector assembly for interconnecting a pair of flat, flexible ribbon cables having a plurality of laterally separated electrical conductors disposed within an insulating covering and having said insulating covering removed from the end portions to be interconnected to expose said conductors, said connector assembly comprising:

a substantially rigid, hollow insulator body having a longitudinal opening defining a pair of spaced edges;

a plurality of laterally spaced reception means in each of said spaced edges, the exposed conductor end portions of the pair of ribbon cables to be interconnected being respectively received from opposite sides, by said reception means and extending through said longitudinal opening into the interior of said hollow body for a distance suflicient to cause a lengthwise overlap of the individual conductors to be connected; and

a longitudinally stretchably, resilient core means insertable into the interior of said hollow body through said longitudinal opening, said core means having an unstretched cross section along its length which is greater than the cross section of the interior of said hollow body to securely urge overlapping conductor end portions against one another and the interior sunface of said hollow body.

4. A connector assembly for interconnecting a pair of flat, flexible ribbon cables having a plurality of laterally separated electrical conductors disposed within an insulating covering and having said insulating covering removed i-rom the end portions to be interconnected to expose said conductors, said connector assembly comprising:

a substantially rigid, hollow insulator body having a longitudinal opening defining a pair of spaced edges;

a plurality ott laterally spaced reception grooves in each of said spaced edges having a width substantially equal to the width of a conductor and a lateral separation substantially equal to the lateral separation between adjacent conductors, the exposed conductor end portions of the pair of ribbon cables to be interconnected being respectively received, from opposite sides, by said reception grooves and extending through said longitudinal opening into the interior of said hollow body for a distance suflicient to cause a lengthwise overlap of the individual conductors to be connected; and

a longitudinally stretchable, resilient core means insertable into the interior of said hollow body through said longitudinal opening, said core means having an unstretched cross section along its length which is greater than the cross section of the interior of said hollow body to securely urge overlapping conductor end portions against one another and the interior surfiace of said hollow body.

5. A connector assembly in accordance with claim 4 in which the interior of said hollow body is cylindrical and the cross section of said core means is circular.

6. A connector assembly in accordance with claim 4 in which the minimum lengthwise overlap of a pair of conductors to be interconnected is not less than the width of the conductor.

7. A connector assembly in accordance with claim 4 in which said hollow body is a cylindrical sleeve and in which said longitudinal opening is a slot of uniform width.

8. A connector assembly in accordance with claim 4 in which said hollow body is a cylindrical sleeve and in which said longitudinal opening defines a cylindrical sector having an arc length between 30 and degrees.

9. A connector assembly in accordance with claim 4 in which said core means includes gripping means in its end portions which extend past the end faces of said hollow body.

10. A connector assembly for interconnecting a pair of flat, flexible ribbon cables having a plurality of laterally separated electrical conductors disposed within an insulating covering and having said insulating covering removed from the end portions to be interconnected to expose said conductors, said connector assembly comprising:

a substantially rigid insulator body having a longitudinal internal bore extending throughout its length and a longitudinal opening in its wall in communication with said bore, said opening having a 'Width that is smaller than the diameter of said bore, said opening defining a pair of substantially parallel opposite edges each adapted to receive the exposed conductor end port-ions of one of said ribbon cables, each edge including reception means for laterally spacing the individual exposed conductors;

the individual exposed conductors being received by said reception means and extending into said bore where each pair of laterally aligned conductors form a lengthwise overlapping conductor portion; and

resilient plug means having a diameter greater than the diameter of said bore disposed in said bore for securely urging said overlapping conductor portions into intimate contact with one another and the interior wall of said bore.

References Cited by the Examiner UNITED STATES PATENTS 3,024,437 3/ 1962 Van Deusen 339-61 X 3,030,604- 4/1962 Moody 339-98 3,038,140 6/ 19-62 Haberland 339-17 X 3,221,096 11/1965 Croghan 339-176 X EDWARD C. ALLEN, Primary Examiner.

W. DONALD MILLER, Examiner. 

1. A CONNECTOR ASSEMBLY FOR INTERCONNECTING A PAIR OF FLAT, FLEXIBLE RIBBON CABLES HAVING A PLURALITY OF LATERALLY SEPARATED ELECTRICAL CONDUCTORS DISPOSED WITHIN AN INSULATING COVERING AND HAVING SAID INSULATING COVERING REMOVED FROM THE END PORTIONS TO BE INTERCONNECTED TO EXPOSE SAID CONDUCTORS, SAID CONNECTOR ASSEMBLY COMPRISING: A SUBSTANTIALLY RIGID, HOLLOW INSULATOR BODY HAVING A LONGITUDINAL OPENING DEFINING A PAIR OF SPACED EDGES, THE EXPOSED CONDUCTOR END PORTIONS OF THE PAIR OF RIBBON CABLES TO BE INTERCONNECTED BEING RESPECTIVELY RECEIVED, FROM OPPOSITE SIDES AND OVER SAID SPACED EDGES THROUGH SAID LONGITUDINAL OPENING BY THE INTERIOR OF SAID HOLLOW BODY OF LENGTHWISE OVERLAPPING CONTACT OF THE INDIVIDUAL CONDUCTORS TO BE CONNECTED; AND RESILIENT CORE MEANS INSERTABLE INTO SAID HOLLOW BODY THROUGH SAID LONGITUDINAL OPENING, SAID CORE MEANS HAVING A CROSS SECTION ALONG ITS LENGTH WHICH IS GREATER THAN THE CROSS SECTION OF THE INTERIOR OF SAID HOLLOW BODY TO SECURELY URGE OVERLAPPING CONDUCTOR END PORTIONS AGAINST ONE ANOTHER AND THE INTERIOR SURFACE OF SAID HOLLOW BODY. 